Shane Scanlon was rescued when Andrew Taylor, a neighbour, entered the house because he was worried that he had not seen the boy or his father Paul for some time.
Dr John Burton, the Hammersmith coroner, recorded an open verdict at the west London inquest after hearing that the cause of Mr Scanlon's death could not be ascertained because of the length of time before he was found. Shane has been staying with a foster family.
His grandmother, Ellen Scanlon, who was accompanied by her daughter Marie, said Mr Scanlon, an unemployed security officer 'seemed to be coping all right' in caring for Shane during his two-year separation from his partner Susan Hill, who has custody of their elder son and did not attend the inquest.
Dr Robert Chapman, a pathologist, said Shane seemed to have survived on cheese and raw eggs. He had a blanket and, apart from looking for food, had tried to stay with his father.
Although the cause of Mr Scanlon's death could not be ascertained, he could not rule out a sudden heart attack or stroke.